Taper Pin Removal From 29K58

[amuckart]

Hi all,

I'm disassembling a 29k58 to overhaul it and there are a couple of taper pins giving me grief. The first is the one holding the thread take-up lever into the arm on the top of the machine, and the second is the one holding that arm onto the head.

As near as I can tell, both should be driven out from the rear of the machine towards the operator, but neither will shift. Both are a little flattened on the small end, but not mushroomed, which makes me wonder if a tool steel pin punch is the right tool to remove them or if I should be using a brass rod or something.

Can anyone offer advice on shifting stubborn taper pins like these?

Cheers.

[BIGGUNDOCTOR]

Make sure that they are going the right direction. One side should be noticeably bigger than the other. Taper pins have a .250" per ft taper.

Do you have a manual that shows the parts in an assembly, or exploded view? IE: are you sure that they are taper pins?

If they are in fact taper pins , and you are mushrooming the end, stopping was the right move. A taper pin should pop out with a good rap or two. Does it have a set screw, or something else used to lock it in place, or has it been Loc-Tited? If Loc-Tite has been used , you will have to warm it up to release it.

Be patient, and don't beak anything.

[amuckart]

I'm pretty sure they're taper pins, and I'm fairly sure I'm trying to tap 'em out in the right direction. Singer seems to be pretty consistent about that sort of thing and the other ones on that axis came out back-to-front.

I don't have a parts chart for the k58 specifically, but I've got two k13s and a parts chart for that from http://parts.singerco.com/IPpartCharts/29K1_4_10_12_18_23_30 TO K33.pdf

The taper pins on the k13s come out back-to-front and shift with a sharp tap, I'm not seeing anything materially different in the construction of the k58, except that the damn things won't shift, even after soaking in penetrant.

There's no set screws holding them in, I've cleaned off the gunk around them to check.

I'm reluctant to apply heat because the finish on the machine is still pretty good (under the accumulated gunk of 20 years in a shed).

Thanks.

[suem]

I'm pretty sure they're taper pins, and I'm fairly sure I'm trying to tap 'em out in the right direction. Singer seems to be pretty consistent about that sort of thing and the other ones on that axis came out back-to-front.

I don't have a parts chart for the k58 specifically, but I've got two k13s and a parts chart for that from http://parts.singerc..._10_12_18_23_30 TO K33.pdf

The taper pins on the k13s come out back-to-front and shift with a sharp tap, I'm not seeing anything materially different in the construction of the k58, except that the damn things won't shift, even after soaking in penetrant.

There's no set screws holding them in, I've cleaned off the gunk around them to check.

I'm reluctant to apply heat because the finish on the machine is still pretty good (under the accumulated gunk of 20 years in a shed).

Thanks.

I had the same problem on my 72, tap from back to front, reinstall front to back. Mine came right out a couple of whacks, but getting it back in .... now that was a different issue, I couldn't get it in all the way and I was afraid I'd break something or mushroom it so far so good nothing's gone south, I hope, and maybe I'm dumb to hope this that eventually vibration and use will loosen it up and it'll either come out or I'll be able to get it in position.

[BIGGUNDOCTOR]

The link you posted is not working.

Hard for me to give any more advice without knowing exactly what you are dealing with. Being a machinist, and a plant mechanic at one time, I have dealt with taper pins before, but they usually pop out without too much fuss.

As to the one not going all the way back in. You may want to pull it out, and replace the pin. If it got swelled during removal, or slightly bent it won't seat correctly. That could be why this one is not coming out, it's bent, or notched. If that is the case, drilling it out to relieve some tension is an option. Pins are inexpensive compared to the parts they hold together. Being a machinist, and having tools like milling machines, and drill presses at my disposal , drilling it out is a "simple" solution for me. If you don't have access to to these it could be a difficult solution. The idea is to drill it out progressively to thin the walls down so that it can collapse and come out. Taper pins are good in that if you do nick the bore, all is not lost. With a standard round pin you might have to open it up to the next bigger size. With a taper pin you just ream it a little deeper. to seat the pin deeper. It is basically a round wedge.

The only other thing I could be is that being in NZ it is opposite than up here

[suem]

As to the one not going all the way back in. You may want to pull it out, and replace the pin. If it got swelled during removal, or slightly bent it won't seat correctly. That could be why this one is not coming out, it's bent, or notched. If that is the case, drilling it out to relieve some tension is an option. Pins are inexpensive compared to the parts they hold together. Being a machinist, and having tools like milling machines, and drill presses at my disposal , drilling it out is a "simple" solution for me. If you don't have access to to these it could be a difficult solution. The idea is to drill it out progressively to thin the walls down so that it can collapse and come out. Taper pins are good in that if you do nick the bore, all is not lost. With a standard round pin you might have to open it up to the next bigger size. With a taper pin you just ream it a little deeper. to seat the pin deeper. It is basically a round wedge.

Right now it won't come out or go back in. Since it's in the upper arm of the 29k 72 (that holds the needle bar onto the arm) I'm terrified of stressing the metal in the arm if I bang it too hard. I'll probably need to investigate your idea of drilling it out, I have a good drill and some titanium bits. I don't suppose heating it a bit may help at this point? I did order some new ones after the original one got stuck of course.

I'm also wondering if the pin not going in may have something to do with the parts involved, it's the pin that holds the needle bar to the "trapeze(?)" that goes up and down on top of the machine, it was tough to get everything in just the right position all lined up. All the parts are replaceable but stil.... Anyway thanks.

Edited May 23, 2011 by suem

[amuckart]

Gah! For some reason the board software obfuscates hyperlink text. The correct link is here

If I do get to the point of having to drill it out I don't mind doing that, I'll just have to order another one since I'm no machinist, but if the hole needs to be bored out, presumably that needs to be done with a special bit/reamer that matches the taper on the pin?

I'm pretty sure they don't go a different way in NZ, they're all made in Scotland

[CowboyBob]

Sometimes they are hard to get out,if never had to drill one in the 100's I've worked on.It might help to support the front part w/a a small nut around the pin & put a hammer against the nut so more force of the hammer from the back will go into the pin.

If you don't understand what I mean & can post a pic tomorrow.

Bob

[amuckart]

Thanks Bob, that makes sense. I'll give that a go tonight.

[BIGGUNDOCTOR]

Strike 2! That link doesn't work either....I get some generic site for Http listings.

That is correct Sewmun, and I failed to think about that aspect, as I just took it for granted. When driving pins it is imperative to have a solid backing , so that the full force is directed into the pin, and not sucked up by the mechanism moving, flexing, etc.. I should have mentione dthat as I have chastised a couple of fellow workers about driving pins out of unsupported parts. I lend them my bench block, and it pops right out, and with less force. The reason I get on them is that if they bend the push rod, it makes more work for me since am the tool maker for the company.